Might want to clarify the Michigan optional essay bullet point in the 'Optional essay' section - it's optional to do any of them and you're not required to do 1 or 2 (but they limit to you at 2 at most). They also allow you to substitute a topic of your own choosing for one of the topics.

I don't think the Yale 250 is techincally optional - the prompt for this question leads me to believe it is required. The Yale application doesn't expressly ask for a personal statement though, they ask in question 10 to add any addtional material that may help them make a decision and note that many applicants include the personal statement they wrote for other LS apps.

Columbia allows additional info such as a ds or why columbia essay. Taken from their faqs:

Can I submit an addendum or additional written materials along with my application?

A: Yes. The Admissions Committee believes that candidates should be able to expand upon aspects of their candidacy that are otherwise not represented in the required materials. Some examples include diversity statements, statements of strong interest in Columbia, explanations of undergraduate and/or LSAT performance, etc. We strongly suggest that applicants use their best judgment, in terms of content and length, when considering the submission of supplemental materials.